Fluid pressure actuating mechanism



Jan. 8, 19x46.

H. J. SCHNEIDER :TAL

FLUID PRESSUREIA-GTUATING MECHANISM 3 Sheets-Sheet 1 Filed Dec. 7, 1943 mysan.

` Jan. 8, 1946. H. J. SCHNEIDER ETAL FLUID PRESSURE ACTUATING MECHAN-ISM Filed Dec. '7, 1943 3 Sheets-Sheet 2 NVENIORS Jan' 8, 1946' H. J. SCHNEIDER :FAL 2,392,772

FLUID PRESSURE ACTUATING MECHANISIVIl 3 sheets-sheet s Filedr Dec; 7. 1,943

@1art1 Patented Jan. 8, 1946 FLUID PRESSURE ACTUATING MECHANISM Henry JL Schneider, Rochester, N'. Y.,v and-y Leon G. Simpson, deceased, late of Inglewood; Calif., by

Ethel V. N. Y.,

Application December 7, 1943 Serial Simpson, administratrix. Rochester,

In Canada July 27', 1942` Claims. (01.,12/1-38l Our present invention relates to iiuicl pressure actuators of' a type in which a preliminary manual operation sets the actuator in motion and an opposite movement of the manual device stalls' and' ultimately reverses the action of said actuator. Devices of this nature can be applied to various 'mechanical problems, but they are particularly applicable to the steering gears of automotive vehicles in attachment with which theyv have the effect ofv applying what is called boosting pressure on the steering gear of they vehicle and thereby reducing the aforesaidl manual eii'ort in turning the ground wheels to a minimum. It is in such an environment that' we choose to describe. our invention. and we have so illustrated an embodiment thereof', it' beingA borne in mind, nevertheless, that there are certain' features of the invention that are particularly applicable in connection with steering gears per se. l

An object of' the invention isy to provide-a device of this general nature thatv will be sensi-A tive to control, powerful in its effect and simpleA both in its construction and, its application to either existing vehiclesA or as a matter of' standard equipment on the" steering mechanismsV of vehicles specially designed for cooperation therewith.

We had issued to' us, January 26', 1942', Patent No. 2,270,742, on the same general type of mechanism. The present invention constitutes an improvement thereon. In the cited prior patent springs were' illustrated andl described as tension-V ing means for supplying frictional resistance to a certain controlling part that was required to bev delayed in its action. With thepresent inventionJ these springs are eliminated andvv air pressure utilizedA instead in a particular way to.A the end thatv chattering or `popping" as it is' called, of the valve controlling memberA asl it` shifts: from; one direction to the; otheris eliminated.. InV other words, useless sensitiveness of the.- valve con.- trolling member is avoided.

Another improvement, over the device of our said earlier patent is the construction and mode, of operation of the intake and exhaust valves to eliminate leakage, arising., in the earlier construction, from diiiiculties of machiningand iit ting the reciprocatory valve thereshown though the same principle is utilized to provide an actuator for the new valves., all. as will be duly described.

To these and other ends, the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fullydescribed., the novel features being pointed out in the claims at' the end of this specification.

In the drawings;

Figure 1' is a side elevation of a portion of the chassis. of a motor vehicle with. a device con,- structed in accordance with and' constituting one embodiment of our invention applied' to the steering mechanism thereof;

Figure 2 is an enlarged side elevation partly' in longitudinal central' section through the cylinder case. only ofv the actuator and connected parts innormal (neutrali positions;

Figure 3 is a view similar to Figure 2. showing the positions of the parts when the manually operated steering gear of Figure l is brought into use to turn the wheels' of the vehicle in one direction, namely, to the right;

Figure 4: is a View similar to Figures 2 and 3,. showing what4 happens when the fluid pressure actuator picks up the movement of the steering columnA and carries on, without further effortv by the driver,` in the iiui'd' pressure;

FigureV 5' is a `further enlarged detail in longitudinal, central section through the rear cylinder head' and adjacent parts;

Figure4 6 is a still further enlarged, fragmentary, centrali',I vertical, section through the front en-d of the cylinder, the piston, and` adjacent parts;A all parts being in positions corresponding' to that' of Figure 2;' f y Figure ,'T isa view similar to Figure 6 with the parts corresponding to the positions shown in Figure 3, the section beingon the line 1"--1 of Figure 13;` I

Figure 8 is a transversesection taken in a plane indicated by the line 8-8" of' Figure 6, looking in the direction of the arrows;

Figure 9 isv a transverse section in a plane taken` onthe line 9 9 of Figure 6';

Figure 10' is a detail side elevation of the friction sleeve and valvek actuator shown in end elevation in Figurel 8 and in. central. transverse section-,in Figure 9;;

Figure 1i isa further enlarged horizontal frag,- mentary detail section through, the same partstaken: on the line I|lz| of Figure. 9';l

Figure 12V is a greatly enlarged, horizontal; section of the piston'. rod bearing on. its Wrist.- pin with fragmentary parts taken on the line tt--iaz of FigureV 2, looking in the direction of the arrowsr Figure- 13 is a section taken on the line I 3-l'3 of Figure 6;

Figure 141 is: an enlarged detail axial section or turning of' the wheels by such up and fseveral views indicate the same parts.

I To first give a general idea of therconstruction and mode of operation of our invention with par- V `ticular reference to its illustrated embodiment,

the iiuid pressure or pneumatic couple comprises a relatively'iixed piston and a movable cylinder.

,The latter is connected to an operating element of the steering gear of the vehicle,V while the piston rod is connected to reactzagainst a xed part of the chassis. yThe piston hasr` two pistonheads and an intervening chamber through all three of which passes a'reciprocatory actuator control-` ling a valve member provided ineach'headi The. 'l'

piston rod is hollow, open to the atmosphere 'and always open to the piston chamber as an 'exhaust' means therefromYV Through the, hollow Ypiston rod 'to oneoffthe heads extendsa pressure supply conduit communicating through a suitable portjin that head with an intake bore connecting poppetvalv'e members in the respective heads.

The actuator itself also acts ,as a valvean'dfhas additional exhaust' ports establishing communication, alternatively, between the piston chamber i and one of the pressure chambers constituted by the V:respective 'piston heads 'and the adjacent cylinder heads. The valve actuator is fixed to a L iioating valve carrier located in the piston chamberv and sliding with frictional pressure on the walls of the cylinder sothat Vit will either seize andmove with'the cylinder when the latter is moved or be dislodged and slide'relatively rto the cylinder under impulse from a 'certain V'pressure communicated to the valve member that it carries. 1 1n other words, the cylinder, through the carrier,

moves the valve actuator slightly in one direction' and the valve is returned by the pressure it builds of course slides the carrier with it.Y The; l valve arrangements are suchthat'when movement of the cylinder is initiated by manual op- At its rear end it is f der head 4.

nected by -a pipe L with our actuating device as hereinafter later described. The forward head of the cylinder I is pivoted at 2 on the pitman pin E. The piston therein is indicated generally at Y 3 comprising the opposite heads 4 and 5 with an intervening annular exhaustl Ychamberl formed therebetween. The pistonY rod Las aforesaid, is hollow 'and extends from the forward piston head through the piston and rear head and through the rea-r cylinder head ofcourse, the latter being provided with anextended bearing I6 and suitable stufling I] as shown in detail in Figure 12. clamped by the'split collar 8 thereof Ato a bearing fitting 9 having a bearing I0 engaging a wristpin II on a xed bracket I2 on lthe, chassis A. This fitting has an opening I3 throughlwhich, as indicated by the arrows, the

'hollow' piston rods exhausts to the atmosphere. "At its inner or forward end, it is similarly in constant exhausting communication through open Y ports Id with pistonchamber i5 (Figure 6). j

Extending through the hollow piston. rodis a similarly tubular pressuresupplyf conduit or pipe I8 threaded into a recess I9 inthe forward cylin- Itsrrear end with suitable fittings passes out through opening I3 inibearing fitting 9 close to the' wrist pin center 8 and terminates in a suitable laterally disposed nipple 20 'to which is v attached the previously described pressure supplyV l in,V both directions.

eration ofthe steering gear ofthe vehicle in the.

usual manner, the valve carrier will move slightly thereby admit'pressure to the appropriate'cylins'teeringgear as desired. As soon Las sufficient isbuilt up in the pressure 1chamber and along with it, operatethewalvev actuator and the steering wheel is held or slightly reversed,

the vcarrier sleeve and valve are returned by the tendency of that pressure against they latter, whereupon thepressure chamber is exhausted into the piston chamber and thence through the hollow connecting Vrod to the atmosphere. The same thing occurs inrreversethrough the pressure chamber at the other end of the cylinder when themanually operated'gearing is similarly manipulated. y Y

Referring more'particularly to the ydrawings and firstV to Figures-1 to 4 thereof, the vehicular environment of the device will be readily recogf nized by those skilled in the art and has been therefore rather conventionally shown to include a chassis Vframe A with front' steering ground wheels B and radius mechanism C connected byv a thrust rod D with the swinging pitman E at thepin E.' The segment F of the latter meshes and vice versa. Carried on the chassis is afluid f pressure (preferably air) tank or source K conwithI afwormG on steering post H having a hand gard t0 pipe L. i

The piston heads 4 and ,5 are, ofcourse, provided with suitable packing ,rings, detachably held in place by the screwsY I1. n

The valve carrier before mentioned occupies the piston chamber I5 and, referring more paraV it Vhas a limited sliding play with reference thereto Its periphery or the shoe surfaces are covered with a frictional packing 25 of somewhat Vthe nature of a brake lining so that'while it 'slides' in the cylinder it tends to move therewith in either direction under the influence of pitman E until opposed in .the manner hereinafter described. It is also s'o moved relatively to the cylinder and the chamberv I5 bythe valve member and valve actuator under the pressure influence .communicated to the latter as hereinafter described.

-E'Xtending through slide'bearin'gs in both piston heads 4 and, 5 andthe chamber I5 at apoint offset from the Centeristhis valve member and valve actuator 25 that is carried by the sleeve 22, being fixed to the latter,1 in the present in-L stance, by a set screw 21 (Figures 6 and 9); .It is longer than the piston and; inthev normal or neutral positions of 'Figures`2 and 6, projects from both heads thereoffnamely; intovthe presi sure chambers 30 and "3 If formed respectively'by the piston head 4 and thev lforwardy end `of the cylinder andthe piston head'p5 andV the' rear cylinder head. This valve member is preferablyl cylindrical and is tubular to form an interior pressure chamber 52 Vwith plugged ends*` having ports 53 and 54 therein, respectively, provided with suitable non-metallic valve seats r55 at their 'inner ends. Resting loosely in the chamber 52 to p'em'ut itse1f onlyaslight.iongitudinarmovement in either direction. When so moved exwhich latter it is of lesser length so that arcane...

tremely` it engages: s.; seat: 55. and closes'one or the other port. Sii-Lit, I The ends of valve member and actuator 25' areflattened and cut back a. ways one. side to form exhaust. ports. 51" and 5t.

When it and al1 partsy are in the normal position of Figure 6 both of. these ports are open as. are ports 53 and' 54A and both piston pressure chambers 30j and 3l', intermediate piston chamber I5, and pressure chamber 52 are all inf communication under neutralized air pressure. But when member 25 is, under the seizing or braking effecty of shoes 22l on the cylinder, moved slightly with the latter, the lengths of the .ports 51! and 58. are such that oneof them will enter the piston:

4A or 5: and close communication between` that pressure 3l or 31 and central piston` chamberI l5 while the other1 one will open wider.

The carrier sleeve or the shoes 2-2 thaty com-l prise it are caused to hug and, on occasion, sei-ze the walls of the cylinder I under the iniluence 0f air pressure other than that in the intermediate piston chamber in which they' are confined. To this end they are connected in the following manner tothe valve member:

Referring more particularly to Figures 8 to 1-1, the friction: carrier embodies a yoke 51 through the knee of which passes `the set screw` 21- that holds it and valve actuator 2B rig-idly together. One of the shoes 22 is pivotedr to one arm of the yoke atA 58 by means of an ear 59. The other arm terminates in a cylinder 60 containing a piston 6I. mounted with a wrist pin 62 upon an ear 63 on the other shoe 2-2. A spring 64 interposed between the latter and the yoke holdsY the shoe lightly against the cylinder wall whatever the pressure in thecylinder. A passage 65 leads from the cylinder down the yoke arm and through valve member 26 to pressure. chamber 52 therein so that the pressure in that chamber controls the pressure. in cylinder B0 acting against 6L When thisv pressure is positive relatively to the intermediate chamber in which the parts lie-, the attached shoe will seize against the cylinder and the reaction will cause the opposite shoe to act iin the same manner against the opposite wall.

Leaving this group of parts for the moment. Without further referenceto their functions we will' now describe the poppet valves by which pressure is admitted, selectively, to the respective cylinder head pressure chambers 30-3I.

These poppet valves embody valve cages consisting of plugs 43 screwed into the piston heads from the outer faces thereof, the two valves being identical. Each, oni-ts inner end, has a seat 44 for a head 45 guided by its stem 46 in a valve stem bore orbearing 41m in the plug. The stem 4'B` is reduced to-a triangular cross sectional area as appearsin Figure l5 so that it will' pass air through the bore and intake passage 41' when the head 45 is unseated and supply the pressure chambers 301 and 3l.

Aligned with the valve plugs. is a bore or chamber 4.1 extending all the waythrough the piston and both heads thereof in the ends oiv which bore the end plugs arev screwed.

A compression spring 48 occupies this chamber with its ends centered on pins 49 ony the respective valve heads so that. its tendency is to. maintain both val-ves closed. The tubular air pressure supply conduit or pipe l 8- communicates with an intake port and passage: 39 in a. piston. head 4': leading to chamber 411. Thus, ,when the; valveqln.

that head is opened, air under pressure is plied through it to pressure chamber 30.

The valves are unseated at this remote point through the medium. ot yoke levers 66 pivoted at. 6&1. on brackets im projecting from the piston. heads. A curved finger 69. on one arm of the lever engages the end of. valve stem. 46V while the other andi longer arm contacted by an end. of: reciprocating element 26. The. result is that; movements of the latter in either direction. from the. neutral position of Figure 6: unseats one. while leaving. the. other undisturbed.

The exhaust ports. I4. are. shown to extend horizontally through the hollow piston rod. 1 and piston 3 to establish exhaust communication to the atmosphere from the. chamberv between. the heads.

The operation of the. devicels. as. follows:

Assume that the. parts are in the. normal. posi'.- tions of Figures 1, zand. 6, thatl is,.with the veht.- cle traveling strait ahead', the piston-ilv ati the. center of cylinder I and the. valve carrier 2.2 centrallyof the piston chamber 5.. In. such al case. both intake valves t5 are. closed by spring 48. Assuming that the driver Wishes. to. turn right, he gives. the: steering. wheel that sort. of an im.- pulse which, through pi'tman E; carries the cylin der forward slightly with referenceto. the. piston a distance indicated by the arc :z: in Figure 3. There being nothing to. oppose. its frlctional en1- gagemen-t therewith under the. preliminary pressure of spring 64, carrier sleeve 22A moves: the. same distance alongl with it. taking actuator 2.6 along with it.

Such lockv between carrier 26" andthe cylinder is sufficient to cause the former to. trip forward. lever 69. and open forward intake valve 4.5 and pressure from the supply conduit is delivered to. and built. up. in forward pressure chamber'v 311', exhaust port 51 being sealed at its inner end but exhaust port 58 for rear pressure chamber 3l. being still open to piston. chamber I '5.v Thus. chamber 3| is open to the atmosphere.` through` the hollow. piston rod and no resisting. compression can develop therein.. This also terminates; for the: moment. the: necessary manual exertion on the.` steering Wheel for. the fluid. pressure. there upon does the work reacting against pistonhead 4'. and continuing the cylinder in itsforward movement,

In the meantime, air has. instantly (with the.; opening of valve 45) rushed through port 55 in valve chamber 52 and, impingingon. the forward end of free valve rod 56 hasprojected it rear-y wardly and closed port 54. Thus the pressurealso builds up in 52 which, through passage 65,. is communicated. to.y cylinder 6,9; of. the carrier causing piston 6.] to press sleeve slices 22 with. greater friction against the cylinder Walls and.

f maintain valve member actuator 26 in position.

In this way the resistance ofV the. friction car-- rier is directly proportional to the work done. It is not heavy at all times` as with the springs. of

our previous patent and hence is kmore sensitive in application and release which is an. important feature of our invention. Upon doing its work this pressure is built up sufliclently to act directly upon valve member' 26 overcoming the friction of its carrier and closing again the intake port 3113;.'

i t At any rate, exhaust port. 46 isthereupo-n opened'.

into. piston. chamber l5 and pressure, chamber 30. is. relieved,fas. earlier described, so that the. two. pressure chambers reassume a. balance. Vahle 25.4 is very sensitiveand. the. pressure builds up very; rapidly in chamber 3B. p Hence, even though the ycommunication 39;-32-35 from the icoming matic release of the valve will occur.

; is he required to turn the wheel more than the fluid isrquickly cut oiffthel valve member con- Y tinues to move to the right in Figure V'7 until the groover establishes' communication between I5 and 3D. In the meantime, bore 29 and its rear por-t 34 have been sealed by piston head 5 while the exhaust port for ,rear pressure chamber 2|V has been continuously in communication withf piston lchamber lEto relieve any pressure on piston head dueto compression therein. VIt will alsobe apparent that continued turning of the steering wheel to the left will set up theV same sequence of happenings in a reverse-direction with the forward intake valve'closed andthat exhaust port open.

The Iextreme combined manual and uid pres- 1 sure actuation of the cylinder and the restoration of the valve and valve carrier to normal is illus- `tratedrin Figure 4. It may be here explained that at no time can the pressure inv either pressure chamber-beso raised and maintained as to cause the piston to contact either cylinder head.

fAnrextreme is shown in Figure 4. This is because the cylinder is made longer than any possible throw of the pitman E. Also inasmuch as vthe pneumatic couple, it will be borne in mind, is .working against a'worm andsegment gear G-F, `it can not itself operate the steering mechanism or cause any resistance to the driver. The lat- V ter simply turns the wheel lightly as long as he wants to turn the ground wheels and then holds it steady, whereupon the above described auto- At no time arc X and that at a time when it does not meet fwith resistance from the couple.

. In fact,vthe valve will keep operating back and forth on slight curves in open driving where the 'j manual effort is so small that it is notworth while calling in the booster, the many right angle turns required in city driving or in traffic or in turning around being where the device is most appreciated. Y Y.

Therefore, in open driving the booster can be temporarily thrown out of operation by turning a, valve M'in the pressure line L arranged con- 3 veniently to the driver, as indicated in* Figure 1.

; Of course, it 'will be obvious to-those skilled in the art that our device may be operated through reversalV by vacuum instead of positive pressure,

withrthe element tube. actuated, of a irictional valve carrier within the piston lchamber .so :en- Y gaging vthe cylinder Walls between the piston heads, a valve Vmember-in the carrier extending through and reciprocatable in both piston heads,` and a `tubular pressure supply conduit extending through the piston rod, certain, of A.the vafore-vv mentioned parts being respectively provided with the following, namely, an exhaust port leading from the piston chamber` tdthe piston rod, an Y exhaust port leading from the latter .to the atmosphere, a passage leadingfrom the pressure supply conduit toY each pressure chamberY between one` or another piston` head andthe ad-V jacent cylinderhead, an intake valve independent'of the reciprocating valve member-in each of said passages, portscontrolled by the position of the reciprocatable valve member* adapted to alternately communicate exhaust fromytherespective pressurerchambers to the piston chamber with reciprocations of such valvemember such, for opening the intake valveof one pres:

sure chamber whenthe exhaust port oi the other is opened. f

2. In a uuid pressure actuator, the combination with a pneumatic ycouple comprising. a cylinder and a two-headed piston operating there in withachamber between-the piston headsand a tubular piston rod acting as an exhaust and extending from the piston chamber through the piston and through ahead of the cylinder, the

cylinder and the piston rod being adapted for con,-- -nection, one with a fixed part andthe other with the element to be actuated, of airictional valve carrier within the piston chamber so engaging the cylinder walls between the pist on,heads,ak

valve member in the carrier-extending through and reciprocatable in bothV piston heads, and aA tubular pressure supply conduit extending through the piston rod, certain of theaforementioned parts being respectively provided with the following, namely, an exhaust port leadingY from the piston chamber 'to the piston rod, an exhaust port leading from the latter to the, atmosphere, a continuous chamber 4Vleading through the piston and embodying a passage leading from the pressure supply conduit to each pressure chamber -between one or anotherY piston Y head and the adjacent cylinder head a poppet vacuum, of course, being'merely negative pressure. In other words, and in general, by Aforcibly exhausting, the atmosphere, to the extent of its weight, can be utilized as the positive pressure medium. In such a case, in general, opening i3 would communicate with the vacuum while conduit I8 would communicate the atmospheric pressure.V

Our invention is particularly useful in con- Ynection with the larger vehicles such as heavy dutyV trucks,rtractors and passenger buses, the

steering .of which by manually operated means alone is an exhausting as well as a relatively.

' slow procedure.

We claim as our invention:

1. In a fluid pressure actuator, the combination with a pneumatic couple comprising a cylinder and a two headed piston operating therein with a chamber between the piston heads,

and a tubular piston rod acting as an exhaust and extending from the piston chamber through the piston and through a head of the cylinder, the cylinder and the piston rod being adapted for connection, one-with a v:fixed part and the other inder and a two-headed piston operating theres in with a chamber between the piston heads, and

a tubular piston rod acting as an exhaust and Y extending from the piston ychamber through the piston and through a head of the cylinder, the cylinder and the piston rod being adapted for' connection, one with a xed part and the other with the element to be actuated, of a frictional valve carrier within the piston chamber so engaging the cylinder Walls between the piston heads, a valve member.'V in the carrier extending through and reciprocatable in both pistoni-heads,

and a, tubular pressure supply conduit extending through the piston rod, certain of the aforementioned parts being respectively provided with the following, namely, an exhaust port leading from the piston chamber to the piston rod, an exhaust port leading from the latter to the atmosphere, a passage leading from the pressure supply conduit to each pressure chamber between one or another piston head and the adjacent cylinder head, a poppet intake valve separate from the reciprocatory valve in each of said passages having a. stem accessible from the chamber ports, ports controlled by the position of the reciprocatable valve member adapted to alternately communicate exhaust from the respective pressure chambers to the pistonhchamber with reciprocations of such valve member, and levers mounted on the piston heads to engage the intake valve stems and actuated by the valve member for opening the intake of one pressure chamber when the exhaust port of thel other is opened.

4. A i'luid pressure actuator constructed in accordance with claim 1 in which the carrier includes friction shoes so engaging the cylinder walls and there is provided further in the combination pneumatically operated means for exerting pressure on the friction shoes proportionately to that in the cylinder head chamber which is under pressure.

5. A uid pressure actuator constructed in accordance with claim 1 in which the carrier includes friction shoes so engaging the cylinder Walls, a yoke having one arm pivoted to one shoe and pivotallyvconnected to the other by a piston and cylinder, the valve member being provided with a pressure chamber having ports at each end leading into the respective cylinder head chambers and a valve rod in such pressure chamber actuated to close one of the last mentioned ports by pressure introduced in the opposite cylinder head chamber, there being a passage in the yoke leading from the valve member chamber to the carrier cylinder and piston.

Deceased. 

